1. Field of the Invention
The present invention relates to a fuel detecting system for an automotive vehicle. More specifically, the invention relates to a fuel detecting system for monitoring fuel consumption in an automotive engine and for detecting residual fuel in a fuel tank which defines a first fuel chamber being in communication with the automotive engine for supplying the fuel thereto and for receiving the fuel recirculating therefrom, and a second chamber supplying the fuel to the first chamber at a supply rate irrespective of consumption rate of the fuel in the first chamber.
2. Description of the Prior Art
As is well known, some fuel tanks for automotive vehicles have an inwardly projecting portion extending inwardly from the bottom of the tank to the essentially middle point of the tank. This types of fuel tank are separated into first and second fuel chambers by means of the inwardly projecting portion. In this types of fuel tank, the fuel in the fuel tank is gradually consumed until the liquid level is equal to the height of the top end of the inwardly projecting portion. Thereafter, the fuel in the second fuel chamber is gradually consumed. The fuel in the first fuel chamber is consumed after the fuel in the sub-tank region is essentially-completely consumed.
A fuel-level detecting system, which indicates the residual quantity of fuel in a tank, provided for this type of fuel tank is described in the Japanese Patent First Publication (Jikkai) Showa No. 57-109924. This fuel detecting system comprises a liquid-level detecting mechanism provided in the first fuel chamber of the tank. The liquid-level detecting mechanism includes a variable resistor associated with a float. The resistance of the variable resistor is modified depending upon the upward and downward movement of the float so that the residual quantity of fuel is expressed by a fuel gauge mounted in the interior of the automotive vehicle. In addition, a lower-limit liquid-level detecting sensor is provided on the bottom of the second fuel chamber of the tank. When the fuel in the second fuel chamber is completely consumed, the sensor detect it so that a residual-quantity warning lamp turns on.
However, the sensor is unrelated to the indication of the residual quantity of fuel. Therefore, while the fuel in the second fuel chamber is consumed after the fuel-level to the height of the top end of the inwardly projecting portion, residual quantity of fuel as indicated by means of the fuel gauge remains constant. As a result, the residual quantity of fuel indicated by the fuel gauge diverges greatly from the actually residual quantity of fuel.